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Journal of Biomechanics

Tyler Schimmoeller, Robb Colbrunn, Tara Nagle, Mark Lobosky, Erica E Neumann, Tammy M Owings, Benjamin Landis, J Eric Jelovsek, Ahmet Erdemir
Ultrasound is a popular and affordable imaging modality, but the nature of freehand ultrasound operation leads to unknown applied loads at non-quantifiable angles. The purpose of this paper was to demonstrate an instrumentation strategy for an ultrasound system to measure probe forces and orientation during freehand imaging to characterize the interaction between the probe and soft-tissue as well as enhance repeatability. The instrumentation included a 6-axis load cell, an inertial measurement unit, and an optional sensor for camera-based motion capture...
November 26, 2018: Journal of Biomechanics
Axel S Koopman, Idsart Kingma, Gert S Faber, Michiel P de Looze, Jaap H van Dieën
With mechanical loading as the main risk factor for LBP in mind, exoskeletons are designed to reduce the load on the back by taking over a part of the required moment. The present study assessed the effect of a passive exoskeleton on back and abdominal muscle activation, hip and lumbar flexion and on the contribution of both the human and the exoskeleton to the L5/S1 net moment, during static bending at five different hand heights. Two configurations of the exoskeleton (LOW & HIGH) differing in angle-torque characteristics were tested...
November 26, 2018: Journal of Biomechanics
Amanda E Stone, Matthew J Terza, Tiphanie E Raffegeau, Chris J Hass
Clinical locomotor research seeks to facilitate adaptation or retention of new walking patterns by providing feedback. Within a split-belt treadmill paradigm, sagittal plane feedback improves adaptation but does not affect retention. Representation of error in this manner is cognitively demanding. However, it is unknown in this paradigm how frontal plane feedback, which may utilize a unique learning process, impacts locomotor adaptation. Frontal plane movement feedback has been shown to impact retention of novel running mechanics but has yet to be evaluated in gait conditions widely applicable within neurorehabilitation, such as walking...
November 26, 2018: Journal of Biomechanics
Aesha Desai, Sandra Geraghty, Delphine Dean
Experimental measurements of cellular mechanical properties have shown large variability in whole-cell mechanical properties between cells from a single population. This heterogeneity has been observed in many cell populations and with several measurement techniques but the sources are not yet fully understood. Cell mechanical properties are directly related to the composition and organization of the cytoskeleton, which is physically coupled to neighboring cells through adherens junctions and to underlying matrix through focal adhesion complexes...
November 22, 2018: Journal of Biomechanics
Toshiki Kobayashi, Michael S Orendurff, Grace Hunt, Fan Gao, Nicholas LeCursi, Lucas S Lincoln, K Bo Foreman
Mechanical tuning of an ankle-foot orthosis (AFO) is important in improving gait in individuals post-stroke. Alignment and resistance are two factors that are tunable in articulated AFOs. The aim of this study was to investigate the effects of changing AFO ankle alignment on lower limb joint kinematics and kinetics with constant dorsiflexion and plantarflexion resistance in individuals post-stroke. Gait analysis was performed on 10 individuals post-stroke under four distinct alignment conditions using an articulated AFO with an ankle joint whose alignment is adjustable in the sagittal plane...
November 22, 2018: Journal of Biomechanics
Michael W Hast, Brett G Hanson, Josh R Baxter
Modeling joint contact in OpenSim is not well understood. This study systematically investigated the variables associated with the elastic foundation contact model within OpenSim by performing a series of controlled benchtop experiment and concomitant simulations. Four metal-on-plastic interactions were modeled, including a model of a total knee replacement (TKR). Load-displacement curves were recorded during cyclic loading between 100 and 750 N. Geometries were imported and into OpenSim and contact mechanics were modeled with the on-board elastic foundation algorithm...
November 22, 2018: Journal of Biomechanics
Martin Grimmer, Brendan T Quinlivan, Sangjun Lee, Philippe Malcolm, Denise Martineli Rossi, Christopher Siviy, Conor J Walsh
Previous ankle exoskeleton assistance techniques that were able to demonstrate metabolic reductions can be categorized into those that delivered moment profiles similar to the biological ankle moment throughout the stance phase, and others that delivered positive power only during push off. Both assistance techniques and a powered-off condition were compared in treadmill walking (1.5 m s-1 ) with a soft exosuit. We hypothesized that both techniques can result in a similar metabolic reduction when providing a similar level of average positive exosuit power at each ankle (0...
November 20, 2018: Journal of Biomechanics
Peter Schwarzenberg, Michael M Maher, James A Harty, Hannah L Dailey
Quantitative assessment of bone fracture healing remains a significant challenge in orthopaedic trauma research. Accordingly, we developed a new technique for assessing bone healing using virtual mechano-structural analysis of computed tomography (CT) scans. CT scans from 19 fractured human tibiae at 12 weeks after surgery were segmented and prepared for finite element analysis (FEA). Boundary conditions were applied to the models to simulate a torsion test that is commonly used to access the structural integrity of long bones in animal models of fracture healing...
November 20, 2018: Journal of Biomechanics
F Beaumont, P Lestriez, P Estocq, R Taiar, F Grappe, G Polidori
The main purpose of this study was to assess the influence of the environmental temperature on both the aerodynamic flow evolving around the bicycle and cycling power output. The CFD method was used to investigate the detailed flow field around the cyclist/bicycle system for a constant speed of 11.1 m/s (40 km/h) without wind. In complement, a mathematical model was used to determine the temperature-dependent power output in the range [-10; 40 °C]. The numerical investigation gives valuable information about the turbulent flow field in the cyclist's wake which evolves accordingly the surrounding temperature...
November 20, 2018: Journal of Biomechanics
M Petrovic, C N Maganaris, F L Bowling, A J M Boulton, N D Reeves
People with diabetes display biomechanical gait alterations compared to controls and have a higher metabolic cost of walking (CoW), but it remains unknown whether differences in the vertical displacement of the body centre of mass (CoM) may play a role in this higher CoW. The aim of this study was to investigate vertical CoM displacement (and step length as a potential underpinning factor) as an explanatory factor in the previously observed increased CoW with diabetes. Thirty-one non-diabetic controls (Ctrl); 22 diabetic patients without peripheral neuropathy (DM) and 14 patients with moderate/severe Diabetic Peripheral Neuropathy (DPN), underwent gait analysis using a motion analysis system and force plates while walking at a range of matched speeds between 0...
November 20, 2018: Journal of Biomechanics
A P Ronkainen, P Tanska, J M Fick, W Herzog, R K Korhonen
Site-specific and depth-dependent properties of cartilage were implemented within a finite element (FE) model to determine if compositional or structural changes in the tissue could explain site-specific alterations of chondrocyte deformations due to cartilage loading in rabbit knee joints 3 days after a partial meniscectomy (PM). Depth-dependent proteoglycan (PG) content, collagen content and collagen orientation in the cartilage extracellular matrix (ECM), and PG content in the pericellular matrix (PCM) were assessed with microscopic and spectroscopic methods...
November 19, 2018: Journal of Biomechanics
Rizwan Arshad, Fumin Pan, Sandra Reitmaier, Hendrik Schmidt
Lumbar lordosis (LL) and the range of motion (RoM) are important physiological measurements when initiating any diagnosis and treatment plan for patients with low back pain. Numerous studies reported differences in LL and the RoM due to age and sex. However, these findings remain contradictory. A systematic review and meta-analysis were performed to synthesize mean values and the differences in LL and the RoM because of age and sex. The quality assessment tool for quantitative studies was applied to assess the methodological quality of the studies included...
November 17, 2018: Journal of Biomechanics
Sandro R Freitas, André Antunes, Pierre Salmon, Bruno Mendes, Telmo Firmino, Carlos Cruz-Montecinos, Mauricio Cerda, João R Vaz
This study sought to examine the shear modulus (i.e., an force index) of three quadriceps muscles [i.e., vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF)] during passive stretching to determine whether epimuscular myofascial force transmission occurs across muscles. Secondly, this study compared the shear modulus between the quadriceps muscles, in both proximal and distal regions. Twelve healthy individuals were assessed during a passive knee flexion maneuver between 0° and 90° of knee flexion with the hip in two positions: flexed (80°) vs...
November 17, 2018: Journal of Biomechanics
Maria N Starodubtseva, Ekaterina F Mitsura, Ivan E Starodubtsev, Irina A Chelnokova, Nikolai I Yegorenkov, Lyudmila I Volkova, Yuriy S Kharin
Hereditary spherocytosis (HS), an erythrocyte membranopathy, is a heterogeneous disease, even at the level of the erythrocyte population. The paper aims at studying the mechanical properties (the Young's modulus, median and RMS roughness of friction force maps; fractal dimension, lacunarity and spatial distribution parameters of lateral force maps) of the cell surface layer of the erythrocytes of two different morphologies (discocytes and spherocytes) in HS using atomic force microscopy. The results of spatial-spectral and fractal analysis showed that the mechanical property maps of the HS spherocyte surface were more structurally homogeneous compared to the maps of HS discocytes...
November 16, 2018: Journal of Biomechanics
Devin Laurence, Colton Ross, Samuel Jett, Cortland Johns, Allyson Echols, Ryan Baumwart, Rheal Towner, Jun Liao, Pietro Bajona, Yi Wu, Chung-Hao Lee
The facilitation of proper blood flow through the heart depends on proper function of heart valve components, and alterations to any component can lead to heart disease or failure. Comprehension of these valvular diseases is reliant on thorough characterization of healthy heart valve structures for use in computational models. Previously, computational models have treated these leaflet structures as a structurally and mechanically homogenous material, which may not be an accurate description of leaflet mechanical response...
November 16, 2018: Journal of Biomechanics
Max A Hammond, Joseph M Wallace, Matthew R Allen, Thomas Siegmund
Microcracking in trabecular bone is responsible both for the mechanical degradation and remodeling of the trabecular bone tissue. Recent results on trabecular bone mechanics have demonstrated that bone tissue microarchitecture, tissue elastic heterogeneity and tissue-level mechanical anisotropy all should be considered to obtain detailed information on the mechanical stress state. The present study investigated the influence of tissue microarchitecture, tissue heterogeneity in elasticity and material separation properties and tissue-level anisotropy on the microcrack formation process...
November 16, 2018: Journal of Biomechanics
Todd C Pataky, Mark A Robinson, Jos Vanrenterghem, John H Challis
The quality with which smoothing algorithms perform is often assessed in simulation by starting with a known 1D datum, adding noise, smoothing the noisy data, then quantifying the difference between the smoothed data and known datum, often using mean-square error (MSE). While effectively summarizing overall difference, MSE fails to capture localized, one-sided errors. This paper describes how smoothing noisy 1D data using a variety of algorithms can introduce systematic bias, and quantifies this bias using the false positive rate (FPR): the probability that a smoothing algorithm will yield a dataset whose 1D mean differs significantly from its true 1D datum...
November 16, 2018: Journal of Biomechanics
David Barbado, Raúl Reina, Alba Roldan, Katina McCulloch, María Campayo-Piernas, Francisco J Vera-Garcia
Trunk control (TC) impairment is a typical feature in individuals with cerebral palsy (CP), but there are lack of methods that allow to quantify the extent to which static and dynamic TC is impaired in adults with moderate-to-severe CP. Thus, the aims of this study were to analyze the reliability of a posturography protocol to assess TC in adults with CP, and quantify their degree of TC impairment compared to a control sample of adults without CP. Forty-seven adults with moderate-to-severe CP and nineteen control participants were assessed via a protocol of static and dynamic seated trunk tasks, performed on a stable and an unstable surface placed on a force-plate...
November 15, 2018: Journal of Biomechanics
Rami M A Al-Dirini, Saulo Martelli, Dermot O'Rourke, Daniel Huff, Ju Zhang, John G Clement, Thor Besier, Mark Taylor
Primary stability is essential for the success of cementless femoral stems. In this study, patient specific finite element (FE) models were used to assess changes in primary stability due to variability in patient anatomy, bone properties and stem alignment for two commonly used cementless femoral stems, Corail® and Summit® (DePuy Synthes, Warsaw, USA). Computed-tomography images of the femur were obtained for 8 males and 8 females. An automated algorithm was used to determine the stem position and size which minimized the endo-cortical space, and then span the plausible surgical envelope of implant positions constrained by the endo-cortical boundary...
November 15, 2018: Journal of Biomechanics
Muhammad Salman, Karim G Sabra
Currently, noninvasive cost-effective techniques capable of quantifying non-uniform degradation of tendon's mechanical and structural properties associated with localized tendon injuries are not readily available. This study demonstrates the applicability of a simple surface-wave elastography (SURF-E) method for assessing the stiffness of the Achilles Tendon by measuring the propagation velocity of surface waves along the tendon in a much broader range of values than currently available Ultrasound-based or MRI-based elastography methods do...
November 15, 2018: Journal of Biomechanics
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